Abstract: This study explored how repeated freeze-thaw cycles affect the quality of Duolang mutton meat, using the longissimus dorsi muscle. After six cycles, measurements were taken for eating quality, safety parameters, texture properties, and indicators related to protein oxidation. Results showed a clear trend of quality degradation in the mutton meat as freeze-thaw cycles increased (P < 0.05). Regarding eating quality, pH first rose and then fell. Water activity and water-holding capacity dropped significantly, while shear force decreased from 35.52 N to 19.98 N. Color stability worsened markedly, with the relative contents of deoxymyoglobin and metmyoglobin increased by 17.81% and 10.17%, respectively, whereas oxymyoglobin declined from 45.98% to 20.11%. Lightness (L^*) value first decreased, showed a partial recovery mid-process, and then fell again. Redness (a^*) and yellowness (b^*) values initially increased before decreasing. For texture, hardness and adhesiveness rose significantly, whereas gumminess and cohesiveness decreased notably. Springiness showed a gradual declining trend (P > 0.05). In terms of safety and oxidation characteristics, the thiobarbituric acid reactive substances (TBARS) value increased from 1.42 mg/kg to 2.35 mg/kg, indicating advancing lipid oxidation. Total volatile basic nitrogen (TVB-N) first increased and then decreased. Total sulfhydryl content fell from 18.59 μmol/g protein to 10.33 μmol/g pro, while carbonyl content rose from 4.61 μmol/g pro to 7.23 μmol/g pro. Disulfide bond content first decreased and later increased, collectively pointing to intensified protein oxidation. In summary, repeated freeze-thaw cycles significantly exacerbated the quality deterioration of Duolang mutton meat by intensifying protein and lipid oxidation and disrupting muscle structure, and the degree of deterioration gradually worsened with increasing number of freeze-thaw cycles.